History of Saguaro Cactus Monitoring in Saguaro National Park, 1939-2007

Saguaro National Monument (now Saguaro National Park) was established in 1933, with the aim of preserving the majestic saguaro cactus (Carnegiea gigantea) and other plants unique to the Sonoran Desert. At that time, some evidence already existed that the saguaro population in the Tucson area was declining. Many factors may have been responsible for the decline, including cattle grazing and deforestation. In addition, major freezes during the winters of 1937, 1940, and 1941 damaged or killed many of the older and larger saguaros.

In response to the obvious saguaro decline observed throughout the monument in the late 1930s, efforts to establish saguaro monitoring plots commenced in 1941. From these early “cactus disease investigations” blossomed a multi-faceted network of saguaro monitoring projects, several of which continue today.